1. Field of the Invention
The present invention generally relates to an ink-jet recording apparatus that comprises a recording head, for ejecting ink droplets from nozzle openings in response to print signals, and an ink cartridge for supplying ink to the recording head.
2. Description of the Related Art
In an ink-jet recording apparatus, which includes a recording head and an ink cartridge for supplying ink to the recording head, an ink supply needle is provided on the recording head and is inserted into and removed from an ink supply port that is formed in the ink cartridge. This arrangement facilitates the supply of ink from the ink cartridge to the recording head.
In FIG. 5 is shown an example of structure in the vicinity of an ink supply needle A. An open portion in an area connecting an ink supply port in needle A to an ink flow path B, which communicates with the recording head, is expanded to form a filter chamber C. A filter D fabricated of unwoven cloth or a mesh material is provided in chamber C. Bubbles which are generated or expanded in the ink cartridge, and dust, are prevented from flowing into the recording head by filter D.
The area of the filter chamber C is increased in cross section and the flow rate of ink is reduced in order to enhance the original bubble capture function of the filter and to prevent the increase in flow path resistance that accompanies the insertion of the filter D. However during an ink filling operation or a recovery operation when the flow rate of the ink passing through the filter D is comparatively increased, bubbles on the filter D can not be completely removed and may remain on the surface of the filter D.
When a bubble E is retained on the filter D, it expands during printing until it covers a large area of the filter D. The bubble reduces the area of the filter D through which ink can pass and causes the flow path resistance to become extremely high. When the flow path resistance is high, the supply of ink to the recording head is interrupted, thereby disabling the printing operation.